This invention relates to a method of separating serum/plasma included in a certain volume of blood, said volume of blood being introduced into a test tube, in which a so-called separating body is also present, after which the test tube is centrifugalized, the blood being separated into a heavy phase containing red blood corpuscles and a light phase containing serum or plasma, the separating body being given such a specific gravity that upon centrifugation it enters a position in the boundary layer between the heavy and light phase. The invention also relates to a device for separation according to the above.
A plurality of various technical methods are known to provide separation of a sample of blood enclosed in a test tube to a heavy phase containing red blood corpuscles and a light phase containing serum.
A general method is arranging a silicon compound having a specific gravity between that of the heavy phase and the light phase on the bottom of a test tube. Upon centrifugation of the sample the silicon compound will form a barrier between the heavy phase and the light phase so that the light phase, i.e. the serum/ plasma can be removed from the test tube while the heavy phase, i.e. the red blood corpuscles, remains in the test tube. However, this technique does not provide any mechanical barrier between the two phases and, moreover, the accumulation of leukocytes and trombocytes in the boundary layer between the two phases is not taken charge of, meaning that the serum/plasma will be "contaminated" by these leukocytes and trombocytes.
It is also known in separation of the kind described above to use a quite mechanical separating body having such as specific gravity that it will adjust itself upon centrifugation of the test tube in the boundary layer between the heavy and the light phase.
The mechanical separating bodies have different types of seals bearing on the walls of the test tube. However, these seals cannot be made too efficient as the separating body must be able to slide within the test tube. Moreover, the accumulation of leukocytes and trombocytes in the boundary layer between the heavy and the light phase is not taken charge of but will "contaminate" the serum/plasma.